Preparation

Make the biscuit dough

• Mix all the dry ingredients in a large bowl. Cut in the chilled butter with two knives or your fingers until the mixture resembles coarse meal. Pour in the heavy cream, mixing with wooden spoon just until the dough comes together. (Overmixing will result in tough biscuits.)

Make the filling

• Melt the butter in a large saucepan over low heat. Slowly stir in the flour with a wooden spoon and cook over medium-low heat, stirring often, until the roux is light golden, about 10 minutes.
• Gradually whisk in the stock, increase the heat to medium-high, and bring the liquid to a simmer, continuing to whisk. Stir in the half-and-half, increase the heat to high, and bring the sauce to a boil, then reduce the heat to low. Add the carrots, celery, onion, bay leaf, thyme, and sage. If using bell pepper, green beans, and/or potatoes, add them now. Stir well and simmer over medium-low heat until the vegetables are tender, 10 to 12 minutes. Remove and discard the herb sprigs and bay leaf and season with salt and pepper. (The sauce can be refrigerated, covered, for up to 2 days; rewarm it gently when you’re ready to make the potpie.)

Assemble and bake the potpie

• Preheat the oven to 350ºF.
• Add the turkey and the remaining vegetables to the sauce and simmer for 5 to 10 minutes, or until the vegetables are just tender. Pour the mixture into a 9-x-13-inch baking dish.
• On a floured surface, roll or pat the biscuit dough out 1/2 inch thick. Using a 2- to 3-inch biscuit cutter or drinking glass, cut rounds out of the dough and cover the top of the potpie. Brush the tops of the biscuits with the melted butter.
• Bake for 30 to 40 minutes, or until the biscuit crust is golden brown and the sauce is bubbling. Serve hot.